The Intel® SSD 600p Series requires an M.2 PCIe NVMe* 3.0 x4. Performance does vary depending on capacity. The 128GB model should allow for a sequential read of up to 770 MB/s, and a sequential write of up to 450 MB/s. Any performance result around the 80 percentile of this should be considered normal.

The ASRock* Z97 Extreme9 comes with one M.2 PCIe Gen3 x4 port, where you should expect full performance. And one M.2 PCIe 2.0 x2 port, lower performance should be expected here due to the older PCIe version and since only 2 lanes are allotted.

Ideally, benchmarking should be performed on an empty drive. Having files on the SSD, or benchmarking while it's being used as a boot drive will not allow the tools to access the full bandwidth required for reliable results.

For benchmarking we can recommend using one of the following tools:

IOmeter* (Most accurate, but more complicated to use, geared for IT Pros)